The present invention relates to an adhesive preparation to be applied to the oral cavity for intraoral administration of a drug.
Conventional preparations for intraoral drug administration include liquid, ointment, jelly, spray and the like. In these preparations, unnecessary leakage of a drug into saliva and migration of the drug into the sites where the drug is not needed is inevitable, because the solution flows, base materials of ointment and jelly dissolve, a spray may be excessively applied and for other reasons. As a result, these preparations are associated with problems in that patients unnecessarily suffer from uncomfortableness, such as bitterness and the like, the rate of utilization of the drug decreases, preventing sufficient drug efficacy, and the like.
There has been recently proposed an intraoral adhesive preparation comprising a water-soluble or water-swellable polymer as a base of an adhesive layer containing a drug, as a preparation having superior adhesive property even on oral mucosa wet with water (e.g., saliva etc.). The proposed intraoral adhesive preparation may be inconvenient as are conventional preparations, because the adhesive layer dissolves or swells with time upon contact with saliva etc. and may come off and fall or the drug may leak and is washed away upon dissolution or swelling.
In recent years, moreover, various percutaneous absorption type pharmaceutical products conatining a pressure-sensitive adhesive have been devised and widely used for integumentary drug administration. Such percutaneous absorption type pharmaceutical products include various embodiments, wherein a typical one is an adhesive sheet type preparation consisting of a pressure-sensitive adhesive layer containing a drug and a polyester film support layer. If this adhesive sheet type preparation has a suitable adhesive power to the oral mucosa, the polyester film would sufficiently block the contact of the adhesive layer with saliva and prevent unnecessary uncomfortableness due to bitterness and the like felt by patients, or decrease in the drug utilization, which could lead to insufficient drug efficacy, because the pressure-sensitive adhesive layer is free of dissolution or leakage of the drug.
Nevertheless, the above-mentioned adhesive sheet type preparation has not been put to practical use for intraoral application. This is because a polyester film used for the above-mentioned adhesive sheet type percutaneously absorptive preparation is considerably stiff even if it is only about 12 xcexcm thick, has many irregularities, and when applied to the oral cavity, where sensitivity is sharp, cannot sufficiently follow curves, which in turn results in poor adhesion and marked uncomfortableness. A thin film is also poor in handling property, making application of the sheet inside the oral cavity not an easy job.
On the other hand, a preparation including a flexible film as a support, such as polyethylene, vinyl chloride and the like, shows fine followability to curves, improving adhesion to the application site, but its flexibility degrades handling property and makes its application inside the oral cavity difficult. A flexible film tends to allow migration of the drug into the inside of a film, making the drug instable.
It is therefore an object of the present invention to provide an intraoral adhesive preparation, wherein an anchor effect of a support and an adhesive plaster layer is fine, adhesion to the surface having irregularities is fine due to superior flexibility, obliterating uncomfortableness such as stiffness, handling property is fine even in a narrow site such as in the oral cavity, and the drug hardly leaks out and is washed away due to saliva.
Accordingly, the present invention provides the following.
The intraoral adhesive preparation of the present invention comprises a support made of a nonwoven fabric mainly made of split type conjugated fibers, and an adhesive plaster layer containing a drug, which is formed on the support, wherein the split type conjugated fiber has an about triangular sectional shape after splitting, where the about triangle has the longest diameter (DL) of 5 xcexcm-15 xcexcm, and the longest line segment (DS), that vertically crosses the longest diameter, of 2 xcexcm-10 xcexcm. The inventive sheet achieves the above-mentioned objects.
In a preferable embodiment, a DL/DS ratio is 1.5-2.5.
In a preferable embodiment, the above-mentioned split type conjugated fiber is obtained by splitting a conjugated fiber consisting of at least two kinds of fiber materials combined radially from the about center of the section, wherein the number of split is not less than 16.
In a preferable embodiment, the above-mentioned nonwoven fabric contains 1 to 50 undivided split type conjugated fibers in a 0.1 mm2 section.
In a preferable embodiment, the above-mentioned nonwoven fabric has a thickness of 300-600 xcexcm, and a density of 0.17-0.25 g/cm3.
In a preferable embodiment, the above-mentioned intraoral adhesive preparation has a shorter diameter of 0.5-1.5 cm and a longer diameter of 1-3 cm.
In the context of the present invention, the term xe2x80x9cabout trianglexe2x80x9d means a triangle in a wide sense, which includes not only mathematical triangle, but about fan, a triangular shape having any one of the sides curved to form a concave or convex, a triangular shape having round triangle apexes resembling a polygon, and the like.
In the present invention, of the line segments from the apex of the about triangle, which is the center of the split type conjugated fiber before division, to the arc of the about triangle (fan shape) forming the outer periphery of the split type conjugated fiber before division, the longest line segment is the longest diameter (length thereof DL). Of the line segments vertically crossing the longest diameter and crossing the circumference of the triangle, the longest line has a length of DS.
In the present invention, the term, xe2x80x9csplit type conjugated fiberxe2x80x9d means a conjugated fiber obtained by compounding and spinning of two or more polymer components having different properties, using a spinneret divided in a predetermined number. The split type conjugated fiber is divided into thinner fibers by extracting one polymer component or by applying a strong impact (i.e., high pressure water stream), like sections of orange get separated when it is cut in thin slices.